Production of metallic titanium



PRGDUCT ION OF METALLIC TITANIUM Alfred C. Loonam, New York, N. Y., assignor to Chilean Nitrate Sales Corporation, New York, N. Y., a corporation of New York No Drawing. Application April 12, 1948, Serial No. 20,592

11 Claims. (Cl. 117-107) This invention relates to the production of metallic titanium and has for an object the provision of an improved method or process for producing high-purity metallic titanium. More particularly, the invention contemplates the provision of an improved method or process for producing high-purity metallic titanium by dissociation of titanium tetraiodide. I

In the preparation of titanium metal of high purity, it has been proposed to reduce a compound of titanium and produce a gaseous product containing titanium tetraiodide which is dissociated through contact with a heated surface to effect dissociation of the titanium and iodine of the titanium tetraiodide with deposition of the separated metallic titanium taking place.

In accordance with heretofore customary procedures, titanium dioxide is subjected to a suitable treatment which will convert the titanium to a form in which it is capable of reacting with iodine to produce titanium tetraiodide. The titanium of the titanium dioxide may be converted into such a suitable form by reduction to the metallic state. Reduction of the titanium of the titanium dioxide is carried out by means of non-carbonaceous reducing agents such as sodium, calcium, magnesium, silicon and aluminum.

The metallic titanium produced by reduction of titanium dioxide with a non-carbonaceous reducing agent can be used to produce titanium tetraiodide. I have found, however, that reduction with carbon produces a product which provides a better reaction material and which is less expensive than the product resulting from reduction by means of non-carbonaceous reducing agents.

I prefer to reduce the titanium of the titanium dioxide with carbon and produce titanium carbide, as I have found iodine will react with titanium carbide rapidly and efficiently at a temperature near 1100 C. I

Titanium carbide can be produced by heating a mixture of titanium and carbon to a temperature of about 105 C. at atmospheric pressures, but the reaction is slow and can be made to go to completion only with drfiiculty. Incompletely reduced material does not react readily with iodine. Therefore, I prefer to carry out the reduction with carbon at a higher temperature. I have found that a highly reactive titanium carbide product maybe obtained by carrying out the reduction at temperatures in the range 1300 C. to 1800 C. At temperatures in the lower portion of the range, I prefer to effect the heating and reduction under a vacuum. Products formed at the lower temperatures under reduced pressures are more highly reactive than products formed at higher temperatures under atmospheric pressure. Thus, for example, titanium carbide formed at 1300 C. under vacuum may be as much as ten percent more reactive than titanium carbide formed at 1800 C. under atmospheric pressure. The advantage of greater reactivity may be offset to some extent by the cost and inconvenience of operating under a vacuum. Normally, I prefer to operate under atmospheric pressure at a high temperature in the neighborhood of 1800 C. in view of the large quantities of gas protates atent duced in the reaction. An electric resistance furnace of the type employed in producing silicon carbide may be employed advantageously in carrying out the reduction of titanium with carbon and the production of titanium carbide.

In order to limit contamination of the titanium carbide, I prefer to employ petroleum coke or charcoal as the reducing agent.

The titanium carbide produced is subjected to the action of iodine vapor at an elevated temperature. I have found that the rate of reaction reaches a maximum at 1100 C. and falls off at lower and higher temperatures.

In carrying out the reaction between iodine and titaniumcarbide at the higher temperatures, I prefer to employ a furnace lined with graphite, as the results of my investi gations indicate that graphite is not attacked at any temperature by iodine vapor. I prefer, also, to employ electrical resistance heating because of ease of control, efiiciency and the absence of any gaseous products of combustion which, if present, might contaminate the titanium tetraiodide produced.

According to a complete process of the invention, titanium dioxide is heated to a temperature in the neighborhood of 1800 C. at atmospheric pressure in the presence of sufiicient carbon to combine with all of the oxygen of the titanium dioxide to reduce the titanium and with all of the reduced titanium to form titanium carbide. The titanium carbide thus produced is subjected to the action of elemental iodine in vapor form at a temperature of about 1100 C. to produce a gaseous product containing titanium tetraiodide. The titanium tetraiodide of the gaseous product thus produced is contacted with a surface heated to and maintained at a temperature in the range 1100 C. to 1700 C. Contact of the titanium tetraiodide with the heated surface results in dissociation of the titanium tetraiodide into elemental or metallic titanium and elemental iodine and deposition on the heated surface of the metallic titanium in a high state of purity.

The gaseous product containing titanium tetraiodide resulting from treatment of titanium carbide with iodine may be treated for the separation of impurities and the production of pure titanium tetraiodide if necessary. Such treatment may include fractional condensation or complete cooling and condensation followed by tractional distillation to produce pure titanium tetraiodide. If the gaseous product is free of impurities, it may be passed directly into contact with the heated surface without any substantial reduction of temperature or loss of heat.

The deposition surface may be formed of tungsten or titanium or other suitable material, and it may be heated in any suitable manner.

The elemental iodine resulting from dissociation of the titanium tetraiodide is returned to the process and utilized in the treatment of additional titanium carbide.

Preferably, the titanium tetraiodide is contacted with the heated surface at a pressure not higher than about 30 mm.

I claim:

1. In a method of recovering titanium in the form of a high-purity metallic product from crude titanium-bearing material, the improvement which comprises treating the crude titanium-bearing material to produce a titanium carbide product subjecting titanium carbide to the action of gaseous iodine at an elevated temperature to produce titanium tetraiodide, and contacting the titanium tetraiodide in vapor form with a heated surface at a temperature in the range 1100 C. to 1700 C. to effect decomposition of the titanium tetraiodide and deposition of metallic titanium on the heated surface.

2. In a method of recovering titanium in the form of a high-purity metallic product from crude titanium-bearing material, the improvement which comprises treating the crude titanium-bearing material to produce a titanium carbide product subjecting titanium carbide to the action of gaseous iodine at an elevated temperature near 1100 C. to produce titanium tetraiodide, and contacting the titanium tetraiodide in vapor form with a heated surface at a temperature in the range 1100 C. to 1700 C. to effect decomposition of the titanium tetraiodide and deposition of metallic titanium on the heated surface.

3. In a method of recovering titanium in the form of a high-purity metallic product from crude titanium-bearing material, the improvement which comprises treating the crude titanium-bearing material to produce a titanium carbide product subjecting titanium carbide to the action of gaseous iodine at an elevated temperature near 1100 C. to form a gaseous product comprising titanium tetraiodide, collecting and condensing the gaseous product, and contacting the titanium tetraiodide in vapor form with a heated surface at a temperature in the range 1100 C. to 1700 C. to effect decomposition of the titanium tetraiodide and deposition of metallic titanium on the heated surface.

4. The method of recovering titanium in the form of a high-purity metallic product from titanium oxide which comprises heating the titanium oxide to an elevated temperature in the presence of sufficient carbonaceous material to reduce titanium of the oxide and form titanium carbide, subjecting the titanium carbide to the action of gaseous iodine at an elevated temperature to produce titanium tetraiodide, and contacting the titanium tetraiodide in vapor form with a heated body at a temperature in the range 1100 C. to 1700 C. to effect dissociation of the titanium tetraiodide with the production of highpurity metallic titanium and with deposition of the metallic titanium thus produced on the heated body.

5. The method of recovering titanium in the form of a high-purity metallic product from titanium oxide which comprises heating the titanium oxide to an elevated temperature in the presence of sufiicient carbonaceous material to reduce titanium of the oxide and form titanium carbide, subjecting the titanium carbide to the action of gaseous iodine at an elevated temperature near 1100 C. to produce titanium tetraiodide, and contacting the titanium tetraiodide in vapor form with a heated body at a 6. The method of recovering titanium in the form of a high-purity metallic product from titanium oxide which comprises heating the titanium oxide to an elevated temperature not substantially lower than 1800 C. at atmospheric pressure in the presence of suflicient carbonaceous material to reduce titanium of the oxide and form titanium carbide, subjecting the titanium carbide to the action of gaseous iodine at an elevated temperature near 1100 C. to form a gaseous product comprising titanium tetraiodide, collecting and condensing the gaseous product, and contacting the titanium tetraiodide in vapor form with a heated body at a temperature in the range 1100 C. to 1700 C. to effect dissociation of the titanium tetraiodide with the production of high-purity metallic titanium and with deposition of the metallic titanium thus produced on the heated body.

7. The method of recovering titanium in the form of a high-purity metallic product from titanium oxide which comprises heating the titanium oxide to an elevated temperature below 1800" C. at a pressure below atmospheric pressure in the presence of sufficient carbonaceous material to reduce titanium of the oxide and form titanium carbide, subjecting the titanium carbide to the action of gaseous iodine at an elevated temperature near 1100 C. to form a gaseous product comprising titanium tetraiodide, collecting and condensing the gaseous product, and contacting the titanium tetraiodide in vapor form with a heated body at a temperature in the range 1100 C. to 1700 C. to efiect dissociation of the titanium tetraiodide with the production of high-purity metallic titanium and With deposition of the metallic titanium thus produced on the heated body.

8. The method of recovering titanium in the form of a high-purity metallic product from titanium oxide which comprises heating the titanium oxide to an elevated temperature near 1300 C. under a high vacuum in the presence of suflicient carbonaceous material to reduce titanium of the oxide and form titanium carbide, subjecting the titanium carbide to the action of gaseous iodine at an elevated temperature to produce titanium tetraiodide, and contacting the titanium tetraiodide in vapor form with a heated body at a temperature in the range 1100 C. to 1700 C. to effect dissociation of the titanium tetraiodide with the production of high-purity metallic titanium and with deposition of the metallic titanium thus produced on the heated body.

9. The method of recovering titanium in the form of a high-purity metallic product from titanium oxide which comprises heating the titanium oxide to an elevated temperature in the presence of sufficient carbonaceous material to reduce titanium of the oxide and form titanium carbide, subjecting the titanium carbide to the action of gaseous iodine at an elevated temperature to produce titanium tetraiodide, and contacting the titanium tetraiodide in vapor form with a heated body of metallic titanium at a temperature in the range 1100 C. to 1700 C. to effect dissociation of the titanium tetraiodide with the production of high-purity metallic titanium and with deposition of the metallic titanium thus produced on the heated body of metallic titanium.

10. The method of recovering titanium in the form of a high-purity metallic product from titanium oxide which comprises heating the titanium oxide to an elevated temperature in the presence of sufficient carbonaceous material to reduce titanium of the oxide and form titanium carbide, subjecting the titanium carbide to the action of gaseous iodine at an elevated temperature near 1100 C. to form a gaseous product comprising titanium tetraiodide, collecting and condensing the gaseous product, and contacting the titanium tetraiodide in vapor form with a heated body of metallic titanium at a temperature in the range 1100 C. to 1700 C. to eifect dissociation of the titanium tetraiodide with the production of high-purity metallic titanium and with deposition of the metallic titanium thus produced on the heated body of metallic titanium.

11. The method of recovering titanium in the form of a high-purity metallic product from titanium oxide which comprises heating the titanium oxide to an elevated temperature near 1300 C. under a high vacuum in the presence of suflicient carbonaceous material to reduce titanium of the oxide and form titanium carbide, subjecting the titanium carbide to the action of gaseous iodine at an elevated temperature to produce titanium tetraiodide, and contacting the titanium tetraiodide in vapor form with a heated body of metallic titanium at a temperature in the range 1100 C. to 1700 C. to etfect dissociation of the titanium tetraiodide with the production of high-purity metallic titanium and with deposition of the metallic titanium thus produced on the heated body of metallic titanium.

References Cited in the file of this patent UNITED STATES PATENTS 1,497,417 Weber June 10, 1924 1,671,213 Van Arkel et al May 29, 1928 1,891,124 Van Arkel et al. Dec. 13, 1932 2,237,503 Ridgeway Apr. 8, 1941 2,393,264 Rentschler et al Jan. 22, 1946 

1. IN A METHOD OF RECOVERING TITANIUM IN THE FORM OF A HIGH-PURITY METALLIC PRODUCT FROM CRUDE TITANIUM-BEAR-. ING MATERIAL, THE IMPROVEMENT WHICH COMPRISES TREATING THE CRUDE TITANIUM-BEARING MATERIAL TO PRODUCE A TITANIUM CARBIDE PRODUCT SUBJECTING TITANIUM CARBIDE TO THE ACTION OF GASEOUS IODINE AT AN ELEVATED TEMPERATURE TO PRODUCE TAINING SAID COMMINUTED MATERIAL INTO AN ELONGATED BARREL IODIDE IN VAPOR FORM WITH A HEATED SURFACE AT A TEMPERATURE IN THE RANGE 1100* C. TO 1700* C. TO EFFECT DECOMPOSITION OF THE TITANIUM TETRAIODIDE AND DEPOSITION OF METALLIC TITANIUM ON THE HEATED SURFACE. 